|Cycling ear warmers & winter hats are for keeping your head warm when the weather isn't.
Most bicycle helmets are well designed for ventilation - which can be unfortunate in the cold. Head and ear protection makes a winter ride much more attractive!
Caps can be made as full beanies, open or mesh top, orcoverage for the forehead and ears. How much is needed is very much a matter of how and where you feel the cold.
Look for: material, wind stopper, ear coverage, desired level of crown coverage, neck coverage, sweat blocking design, water resistance, versatility